WebSphere Starting Problem

Hi, i am trying to start websphere Admin Server it is giving below database error.i have installed websphere Http server and DB2 in my system.could anybody explain what is the problem and also i need documentation for websphere application server. Error is : [02.11.27 22:35:40:621 GMT+05:30] 7d6e7cdd AdminServer F ADMS0007E: Could not load database driver COM.ibm.db2.jdbc.DB2ConnectionPoolDataSourcejava.lang.Throwable at com.ibm.ejs.ras.TraceLogger.fatalEvent(TraceLogger.java:219) at com.ibm.ejs.ras.TraceEventGeneratorImpl.fireTraceEvent(Tr.java:1402) at com.ibm.ejs.ras.TraceEventGeneratorImpl.fireTraceEvent(Tr.java:1346) at com.ibm.ejs.ras.Tr.fatal(Tr.java:854) at com.ibm.ejs.sm.server.AdminServer.initializeRuntime0(AdminServer.java:1096) at com.ibm.ws.runtime.Server.initializeRuntime(Server.java:882) at com.ibm.ejs.sm.server.AdminServer.main(AdminServer.java:391) at java.lang.reflect.Method.invoke(Native Method) at com.ibm.ws.bootstrap.WSLauncher.main(WSLauncher.java:158) ADMS0007E: Could not load database driver COM.ibm.db2.jdbc.DB2ConnectionPoolDataSourcejava.lang.Throwable at com.ibm.ejs.ras.TraceEventGeneratorImpl.fireTraceEvent(Tr.java:1462) at com.ibm.ejs.ras.TraceEventGeneratorImpl.fireTraceEvent(Tr.java:1346) at com.ibm.ejs.ras.Tr.fatal(Tr.java:854) at com.ibm.ejs.sm.server.AdminServer.initializeRuntime0(AdminServer.java:1096) at com.ibm.ws.runtime.Server.initializeRuntime(Server.java:882) at com.ibm.ejs.sm.server.AdminServer.main(AdminServer.java:391) at java.lang.reflect.Method.invoke(Native Method) at com.ibm.ws.bootstrap.WSLauncher.main(WSLauncher.java:158)